1. Field of the Invention
This invention relates to integrated circuit (IC) control terminal drivers for switching amplifiers and other switching applications having a split power supply and a floating input, and more specifically to such drivers in which the static well associated with the signal input circuitry includes no logic circuits and therefore does not require a power supply input for that portion of the chip.
The invention is described in the context of a Class D audio amplifier, but the invention also has utility in other switching applications in which + and − bus supplies are required for series connected power transistors such as MOSFETS or IGBTS used to drive a load from a common node between the transistors.
2. Relevant Art
The Class D amplifier is representative of many switching applications, amplifiers, in which a gate driver for a pair of high and low side switches must accommodate an input signal lying close to a ground potential between the high and low side bus voltages. In the construction of the required IC gate driver, there must be two isolated wells, one for driving the high side switch and the other for receiving the input signal.
Conventionally, logic circuits are required in both wells, and consequently, power supplies for both wells are also required. Since space and packaging costs are always a factor in ICS, any architecture which permits decreasing the size of the chip or otherwise permitting employment of a smaller or less expensive package can represent a significant commercial advantage.